维基百科

File:BiodegradablePlasticUtensils1.jpg

原始文件 ‎（2,700 × 1,757像素，文件大小：559 KB，MIME类型：image/jpeg）

摘要

描述
English: Knives, forks, and spoons made from a biodegradable starch-polyester material.

The photo has been realized using the photoelasticity method, an experimental method which gets a fairly accurate picture of stress distribution even around abrupt discontinuities in a material.

When a ray of plane polarised light is passed through a photoelastic material, it gets resolved along the two principal stress directions and each of these components experiences different refractive indices. The difference in the refractive indices leads to a relative phase retardation between the two component waves.

The setup used to photograph this photo was probably composed of:

  • A regular light source, with a quarter-wave plate installed to polarize the emerging light
  • A regular photo camera, with a quarter-wave plate installed in front of the lens

Light and camera being installed and oriented in the same direction, the two

quarter-wave plates were turned with the polarizing axis in the same direction.
Français : Couteaux, fourchettes et cuillères biodégradables en polyester à base d'amidon.
Português: Facas, garfos e colheres fabricadas com um material poliéster biodegradável à base de amido. A foto foi tirada usando o método fotoelástico, um método experimental que fornece uma imagem bastante precisa da distribuição do stress mesmo que o material possua descontinuidades abruptas.
Tiếng Việt: Dao, nĩa, muỗng được làm từ một loại vật liệu bột sợi tổng hợp có khả năng phân huỷ sinh học.
日期 未知日期
Unknown date
来源

United States Department of Agriculture (link)
noise removed with a Gaussian blur in The GIMP

This image was released by the Agricultural Research Service, the research agency of the United States Department of Agriculture, with the ID k7245-1 (next).

This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required. See Commons:Licensing.

العربية | English | français | македонски | +/−

作者 Scott Bauer
授权
(二次使用本文件)
Public domain
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Knives, forks, and spoons made from a biodegradable starch-polyester material.

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c0d5eaf9ea4bacc5e6cbcf72cf44a71b96a9f3d4

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当前2007年4月22日 (日) 21:512007年4月22日 (日) 21:51版本的缩略图2,700 × 1,757（559 KB）17Drew~commonswikidarkened background
2007年2月14日 (三) 18:142007年2月14日 (三) 18:14版本的缩略图2,700 × 1,757（1.96 MB）17Drew~commonswiki{{Information |Description=knives, forks, and spoons made from a biodegradable starch-polyester material |Source=United States Department of Agriculture ([http://www.ars.usda.gov/is/graphics/photos/k7245-1.htm link])<br>noise removed with a Gaussian blur

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